Fuel flow measurements from NH 1.5 cups/12 oz per min

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Model T Ford Forum: Forum 2015: Fuel flow measurements from NH 1.5 cups/12 oz per min
Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, August 24, 2015 - 05:15 am:

My 26 Speedster (NH) doesn't seem to rev out enough on the open road and climbs slower than my 27 Coupe running a vaporizer even though its lighter. I'm thinking maybe the fuel flow is the issue so I temp fitted a 6v pump and then a pressure regulator to compare the 3 outputs.
The cowl tank has a few bits of flake/grit in it and it can't be removed so I have a paper filter in the line maybe restricting the flow a little when under full load.
Today I undone the drain t piece under the NH and measured at full flow how much run out in 60 secs...pic 1.

I then plumbed up the fuel pump, turned it on and measured the flow from the same spot for the same time...pic 2.

Last time I tested the fuel pump it kept blowing fuel out the side of the NH so I now fitted the regulator but don't have a method to test the pressure so turned the pump on with my thumb over the outlet hose. When I took my thumb off it blew a strong burst of fuel then settled down to a flow. I adjusted the regulator a fair amount until only a light burst when thumb was removed after buildup.
I plumbed up & then ran the pump & took another measurement from the Holley...pic 3 which looks about the same amount as gravity feed in pic 1.
Only advantage is the pressure should now stay constant no matter how much is fuel is consumed.
Test run showed a smooth constant running engine with no jerks or slight missing which seemed better than under gravity feed however it had no more top speed and the steep hill test also showed no noticeable improvement.
Do you think I should increase the pressure? Is there a simple way of testing the pressure?
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Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, August 24, 2015 - 05:16 am:


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Zibell, Huntsville, AL on Monday, August 24, 2015 - 09:01 am:

There is more than fuel flow that influences performance. The coupe may just have a stronger engine. Have you compared compression readings between the two cars? The speedster may have more drag from the rest of the power train as well. Also instead of a paper filter, you may want to try a glass bowl sediment trap as other here use.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andy Clary on Monday, August 24, 2015 - 10:48 am:

Your fuel flow seems low, does your carb have a grosse jet? Like John said you may have other problems but even 22 oz in a minute isn't much fuel. Removing the grosse jet and installing a stock needle and seat made a huge difference in hill climbing of my coupe.

Andy


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Monday, August 24, 2015 - 11:23 am:

22 oz a minute( nearly 1 1/2 pints) figures out to be 10.32 gallons an hour, more than a stock tank full. 12 oz(3/4 pint per minute) seems fairly high since that is 5.63 gallons per hour. I have never seen a T that could burn that much. Would you happen to have a high speed ring and pinion in the speedster by chance?


Top of pagePrevious messageNext messageBottom of page Link to this message  By David L Corman on Monday, August 24, 2015 - 01:24 pm:

22 oz a minute( nearly 1 1/2 pints) figures out to be 10.32 gallons an hour, more than a stock tank full. 12 oz(3/4 pint per minute) seems fairly high since that is 5.63 gallons per hour. I have never seen a T that could burn that much. Would you happen to have a high speed ring and pinion in the speedster by chance?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andy Clary on Monday, August 24, 2015 - 04:38 pm:

Fuel may not be Kevin's problem but he's not getting much. Flow will also vary with fuel level and filters are a common problem. Also if you are using the round chrome pressure regulator, they can be unreliable.

Andy


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, August 24, 2015 - 05:39 pm:

John, Yes the Coupe has very high compression running a Z head but its not a flyer going up my trial steep climb and top speed is about average. The speedster motor is sound and feels like very good compression via the crank but 35 mph is about top. Its not revving out enough and feels like I'm only using 3/4 throttle. I've checked the linkages. It runs fine, idles nice just missing a bit at the end and under load.
Andy the car was stored for over 5 yrs before I brought it a few months ago, I pulled apart the Carb but not sure what jet it has. I have a heap of spares including about 8 Carby's maybe I try another one to compare. I'm not convinced the flow is too low.
David, what your saying about usage makes sense. I don't believe the gearing is different to my Coupe besides if it was higher it would rev right out plus climb my steep hill better than the Coupe and if lower it wouldn't pull away in top after turning corners as it does.
Andy - When I done the pressure test i had the hose running into a bin and it was flowing more than enough before fitting to the carby so I don't think its the regulator. Its not a Chrome unit, looks to be an new old stock solid construction.
I have several filters in the line but the fuel pump is handling all them.
The frustration is the car is running smooth but just lacks top end etc not that I'd use the speed but a comfortable achievable cruising speed of 60 k's (36 mph) in any conditions would be nice. My Coupe purrs at that.
The reality is I'll probably remove the pump etc in the end as it hasn't given any improvement, I finally tracked down a glass bowl sediment trap as you referred to John last week but its going on the Coupe so if I can find another one I'll fit that to the speedster. An ideal unit is one with a shut off valve built in. I found a really old one on the wall in a diesel injection shop in town last week but he wouldn't sell his collectors piece...bugger!
Thanks for your feedback guys


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, August 24, 2015 - 06:15 pm:

Here a video of the flow with pump on & regulator fitted -

https://www.youtube.com/watch?v=pXfCSprO20I


Top of pagePrevious messageNext messageBottom of page Link to this message  By Walt Berdan, Bellevue, WA on Monday, August 24, 2015 - 06:24 pm:

Kevin, Have you double checked the timing? Sounds like it is possibly running somewhat retarded. OK to good low to mid range power but not much top end could be ignition related. Are you using coils or a distributor on the speedster? If coils, is the mag good or are you running on battery. On a stock ignition, my 26 Coupe ran nice on 6 volt battery to the coils at low to mid RPM but had poor top end. Running on mag woke it right up. (Bit of heresy maybe but an E-Timer on 6 volts runs even smoother on the Coupe.)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Monday, August 24, 2015 - 06:31 pm:

Walt it runs coils, I've cleaned and lubed the timer.
The Mag is fine, its 6v and runs better on Mag and will crank start on mag.
I always drive on mag and I have adjusted the timer lever as I go and it sits about right position. I haven't actually tried switching it to batt when opened up, will do today.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Walt Berdan, Bellevue, WA on Monday, August 24, 2015 - 06:38 pm:

With everything in good to decent working order I would expect performance to be better on mag than on 6 volts. Folks with better knowledge and test equipment than I have shown a consistent power boost when using a good mag. 12 volts did better than 6 volts for coil ignition but mag was best.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Zibell, Huntsville, AL on Monday, August 24, 2015 - 10:51 pm:

Kevin, Guessing at compression figures doesn't tell anyone anything. Most of all you who really needs the information. Do you have a compression tester to get actual readings?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, August 25, 2015 - 02:45 am:

Gave it a compression test, they range from 52 to 55 psi. I'm happy with that. I took it for a long test run today and it performed better on the hill climb this time. It takes about 5 mins open road to get there so should be up to temp.
Remembering I use the same GPS speedo for both cars.
First test was done as usual, swoop around the right angle corner on the bottom as fast as possible and open it up, it slowed to 23 mph on the hill. The Coupe drops to 21 mph so that was slightly better, although the Coupe is heavier car plus there is usually two of us in it plus spares, tools & jack in the boot.
I then parked in a lay-by at the top for a few minutes while I took notes & left the motor idling then drove down & tried again.
This time with a standing start at the corner so it should be worse but was surprised to find it only dropped to 25.5 mph this time! That's 2.5 mph better from a stand, I wonder if it goes better when running a higher temperature? I will test this again tomorrow.

Top speed no improvement, 40 mph is max. Flat road along the Canal with no wind and only one person about 33 - 35 mph is really about it, still sounds like its not revving out.
The plugs looked good when I had them out, I cleaned them while I had them out anyway and it now sounds like it revs a bit quicker.
So tomorrow I will try it again with clean plugs, then again after idling for awhile then I might top the fuel tank with 96 octane (I always use 91) just for a comparison.
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Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Kossor - Kenilworth, NJ on Tuesday, August 25, 2015 - 12:38 pm:

Magneto is about as good as 12V battery based on data I took for an A/B comparison using the TDAS to capture engine RPM and vehicle speed using the same set of ECCT adjusted coils and all other variables constant or as close as possible. Performance is notably degraded operating on 6V battery for further reference. Does anyone have test data that indicates engine performance operating on magneto is actually better than 12V battery?

Mag vs 6V vs 12V

Timing is, of course, a significant factor for engine performance but there are other variables than just the timer position. Coil to coil dwell time to fire and timer contact to contact variation both induce ignition timing variation. Coil box contact bounce and arcing are also factors which can cause timing variation.

One easy test to perform is installing the coils from the 27 Roadster in the 26 Speedster to see if coil to coil variation is an issue. Next would be swapping the timers. Coil box contact variation can be minimized by ensuring the contacts are clean and the lid fits tight and keeps the coils in position. Coil box arcing is more difficult to detect and eliminate unless you have a plastic insert rather than the original wood. If none of those tests is helpful in tracking down the root cause for performance differences, then engine variables may be responsible; cylinder displacement, valves, carburetor, etc. Good luck tracking down the root cause. Looking forward to your next report.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Tuesday, August 25, 2015 - 05:21 pm:

Mike thanks for all that it is interesting.
I plan to trial today what I described and then I might move to the coils as you suggest.
I have a box of Carby's somewhere so that will be the next option after all the above.
Thanks


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Wednesday, August 26, 2015 - 02:10 am:

A little slower on the hill today although I had a passenger but it revved out better and topped out at 43 mph. I could cruise much easier at 36 mph for some reason.
I then topped up from 2 gallons to full tank with 96 Octane. Made a bit of difference of maybe 3 mph even though it would have been slightly heavier. On this subject our petrol price has dropped 90c a US gallon the last few days? Mind you it's still $7.60 a us gallon lol.
Might remove the fuel pump tomorrow and compare again then check the coils.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, August 27, 2015 - 07:22 pm:

Yesterdays test run went better. I was solo again and it climbed the hill best it ever had, wouldn't have thought 55kg would effect it that much.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, September 03, 2015 - 04:10 am:

Update - The car wouldn't start the other day so I removed the carby and cleaned it out. Gave the needle a slight twist with sand paper and refitted. It started right up. The car is running really smooth since with no jerking at any rev range and pulls away from a slow speed great. I have been playing with a dash cam and taking several test runs up the hill comparing notes. I haven't looked at the coils etc as its running so sweetly I'll leave well alone.
It also seems to be constant pulling power now, 34 mph at the bottom of my test hill reducing to 26 mph near the top.
I have tried turning the fuel pump off as I climb so its running on bowl fuel with no pump assist and it climbs just the same so I guess the fuel pump isn't adding to the power.
This is much better hill speed than my Coupe by memory but I'm looking forward to comparing again. Lighter Speedster (tested @ 50 psi compression) running NH v Heavier Coupe running vaporizer plus a Z head (tested @ 90 psi). The Coupes new head gasket should be here tomorrow.
Here is a video of today's run -

https://www.youtube.com/watch?v=i53qUZoLgx0

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Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Thursday, September 03, 2015 - 04:41 am:

So it's running better the more you drive it?
Maybe it wasn't driven much after the last engine overhaul, so it's starting to loosening up first now?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Thursday, September 03, 2015 - 05:44 am:

Don't think so Roger it was driven on Rally's often from what I hear but who knows for sure as the previous owner has died. I'm hoping the Carby just needed another clean. I know there is a bit of crap in the tank and I found the tank can't be removed (I tried) so i have 2 filters in the system. I'll monitor it and try to do as many miles as I can every day and see if it keeps running so good. I'm keen to un-plumb the fuel pump and see how it runs but the main issue will be filters in a gravity system might be too restrictive. Perhaps I just plumb up the 6v pump permanently and tidy and review it again over the summer.
Its a pleasure to drive at the moment.


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